The present invention relates to a refrigeration system including a dual-opposed piston linear compressor, and more particularly to an application of an economizer cycle to the linear compressor.
In refrigeration systems, such as those used in cooling display cases of refrigeration merchandisers, it is necessary to maintain a constant temperature in the display cases to ensure the quality and condition of the stored commodity. Many factors cause varying cooling loads on evaporators cooling display cases. Therefore, selective operation of the compressor of the refrigeration system at different cooling capacities corresponds to the cooling demand of the evaporators. Further, as ambient outdoor temperature decreases, compressor loading typically decreases due to lower system lift. In refrigeration systems utilizing existing scroll and screw compressors, an economizer cycle is used to increase the refrigeration capacity and improve efficiency of the refrigeration system. In the economizer cycle of existing scroll and screw compressors, gas pockets in the compressor create a second “piston” as the mechanical elements of the compressor proceed through the compression process.
Further, scroll compressors use oil for operation, which results in inefficient performance due to oil film on evaporator and condenser surfaces, requires the use of expensive oil management components, and increases the installation cost of the refrigeration system. Some refrigeration systems utilize a linear compressor, which provides variable capacity control of the refrigeration system.